Light emitting device package

ABSTRACT

Embodiments include a light emitting device package. The light emitting device package comprises a housing including a cavity; a light emitting device positioned in the cavity; a lead frame including a first section electrically connected to the light emitting device in the cavity, a second section, which penetrates the housing, extending from the first section and a third section, which is exposed to outside air, extending from the second section; and a metal layer positioned on an area defined by a distance which is distant from the housing in the second section of the lead frame.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of co-pending U.S. patent applicationSer. No. 12/720,235 filed on Mar. 9, 2010, which claims priority under35. U.S.C §119(e) to Korean Patent Application No. 10-2009-0020064,filed in the Republic of Korea on Mar. 10, 2009, Korean PatentApplication No. 10-2010-0020041, filed in the Republic of Korea on Mar.5, 2010, Korean Patent Application No. 10-2010-0020043, filed in theRepublic of Korea on Mar. 5, 2010, the entire contents of which arehereby incorporated herein by reference.

BACKGROUND

1. Field

The present application relates to a light emitting device package and amanufacture method thereof.

Group III-V nitride semiconductor is in the limelight as a main materialof a light emitting device such as a light emitting diode or a laserdiode because of its physical and chemical characteristics. The groupIII-V nitride semiconductor normally has a semiconductor material havinga following combination equation.

In_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1, 0≦x+y≦1)

The light emitting diode changes electricity to light or infrared lightby using its characteristics as a combination semiconductor so that ittransmits signal, and the light emitting diode is used as a lightsource, which is a kind of semiconductor device.

The light emitting diode or the laser diode using nitride semiconductormaterial like this is widely used in a light emitting device, and usedas a light source of various products such as a light emitting unit ofkey pad of a mobile phone, an electric sign and lighting, etc.

SUMMARY

One embodiment of the present invention provides a light emitting devicepackage comprising: a housing including a cavity; a light emittingdevice positioned in the cavity; a lead frame including a first sectionelectrically connected to the light emitting device in the cavity, asecond section, which penetrates the housing, extending from the firstsection and a third section, which is exposed to outside air, extendingfrom the second section; and a metal layer positioned on an area definedby a distance which is distant from the housing in the second section ofthe lead frame.

Another embodiment of the present invention provides a light emittingdevice package comprising: a housing including a cavity; a lightemitting device positioned in the cavity; a lead frame including a firstsection electrically connected to the light emitting device in thecavity, a second section, which penetrates the housing, extending fromthe first section and a third section, which is exposed to outside air,extending from the second section; and a metal layer positioned in anarea defined by a distance which is distant from the housing in thesecond section of the lead frame to prevent moisture from entering thearea.

In addition, another embodiment of the present invention provides alight emitting device package comprising: a housing including a cavity;a light emitting device positioned in the cavity; a lead frame includinga first section electrically connected to the light emitting device inthe cavity, a second section, which penetrates the housing, extendingfrom the first section and a third section, which is exposed to outsideair, extending from the second section; and an sealant for blocking anarea from outside air, which is defined by a distance from the housingin the second section of the lead frame.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent to those of ordinary skill in the art bydescribing in detail preferred embodiments thereof with reference to theattached drawings, in which:

FIG. 1 is a cross sectional view for showing a structure of a lightemitting device package according to a first embodiment of the presentinvention;

FIG. 2 is an another cross sectional view for showing a structure of alight emitting device package according to a first embodiment of thepresent invention;

FIG. 3 is a cross sectional view for showing a light emitting devicepackage according to a second embodiment of the present invention;

FIGS. 4-7 are views of showing a manufacture process of the lightemitting device package according to the first embodiment;

FIG. 8 is a view for showing a light emitting device package accordingto a third embodiment of the present invention;

FIGS. 9-12 are views of showing a manufacture process of the lightemitting device package according to the second embodiment; and

FIG. 13 is a view for showing a light emitting device package accordingto a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Above all, a theoretical background relating to the present invention isdescribed in detail with respect to appended drawings.

FIG. 1 is a cross sectional view for showing a structure of a lightemitting device package according to a first embodiment of the presentinvention.

As shown in FIG. 1, the light emitting device package 100 according tothe first embodiment comprises a housing 110 having a cavity 114, afirst and a second lead frame 131, 132, a light emitting device 120 andan encapsulant 130.

The housing 110 may be made of PCB, a ceramic substrate or a resin, andthe housing is formed of Polyphthalamide resin PPA in this embodiment.The housing 110 includes a lower housing 111 and an upper housing 112.The lower housing 111 and the upper housing 112 may be formed integrallywith the first, second lead frame 131, 132 by injection molding, or theupper housing 112 may be joined on the lower housing 111 and the firstand second lead frame 131, 132.

The housing 110 of the first embodiment comprises the lower housing 111and the upper housing 112 which are formed integrally, and forconvenience separate reference numbers are shown for the upper housingand the lower housing.

The first and the second lead frame 131, 132 penetrate the housing 110,and the frames are installed in the cavity of the housing and at theoutside of the housing. The first embodiment shows the two lead frames131,132 and however the number of the lead frames may be more than threeaccording to a design of the light emitting device package.

Each of the first lead frame and the second lead frame 131, 132comprises a first section positioned in the cavity, a second sectionextending from the first section and surrounded by the housing, and athird section extending from the second section and exposed at theoutside of the housing. In addition, the first lead frame 131 and thesecond lead frame 132 are electrically connected to the light emittingdevice 120 in order to supply power to the light emitting device.

A shape of the cavity 114 which is shown in top view may be circle orpolygon, and a surrounding surface 116 forming the cavity 114 of thehousing may be vertical or inclined to a top surface of the lowerhousing 111.

The light emitting device 120 is positioned in the cavity 114 on/overthe first lead frame 131 or the second lead frame 132. The lightemitting device 120 is electrically connected to the first lead frame131 and the second lead frame 132 through a wire 122.

Although not shown, the light emitting device 120 may be connected tothe first lead frame 131 and the second lead frame 132 in variousmanners. For example, the device may be connected to the first leadframe 131 and the second lead frame 132 by using a flip bonding methodwithout wire, or the device may be die-boned to the second lead frame132 and connected to the first lead frame 131 through a wire.

As shown in FIG. 2, the light emitting device 120 is electricallyconnected to the first lead frame through a wire 122, and the lightemitting device 120 itself may be connected to the second lead frame. Inaddition, although not shown, the light emitting device 120 may bedirectly connected to the first lead frame 131 and connected to thesecond lead frame 132 through a wire 122.

The light emitting device 120 may be positioned in the cavity or in thehousing 110. In addition, the light emitting device 120 may bepositioned on another lead frame, not the first lead frame 131 and thesecond lead frame 132.

The light emitting device 120 may be a light emitting diode chip foremitting red, green or blue light or a light emitting diode chip foremitting ultraviolet light.

An encapsulant 130 is filled in the cavity 114 of the housing. Theencapsulant 130 may be made of transparent resin such as silicon resinor epoxy resin, and it may include a fluorescent material which isentirely or partly distributed in the transparent resin. The first leadframe 131 and the second lead frame 132 penetrate the housing, and aredivided into at least two parts so that each of the lead frame 131, 132may be exposed at the outside of the housing 110.

In addition, the first lead frame 131 and the second lead frame 132 maybe respectively bended to an outside surface of the housing 110 by atrim process and a forming process. In the first embodiment, the firstlead frame 131 and the second lead frame 132 are bended to contact aside surface and a bottom surface of the lower housing 111.

The first lead frame 131 and the second lead frame 132 may be made of ametal or an alloy having copper Cu as a main component, and the framesmay have on its surface more than one plating layer such as a nickelplating layer, a gold plating layer, and a silver plating layer. In thisembodiment, a silver plating layer (not shown) is formed on the firstlead frame 131 and the second lead frame 132.

Meantime, each of the second section 131-2, 132-2 of the first leadframe 131 and the second lead frame 132 which is surrounded by thehousing by penetrating the housing has a boundary surface with thehousing. The second section of the respective lead frame does notcontact entirely with the housing, and its certain part is distant fromthe housing. In other words, while the first lead frame 131 and thesecond lead frame 132 passes through a trim process and a formingprocess, and the frames 131, 132 do not contact tightly with the housing110 and may be separated from the housing 110.

Main reason is a stress at a boundary surface where the first, secondlead frame and the housing contact each other, and a side reason is thatthe first, second lead frame and the housing are made of differentmaterials having different heat-inflation coefficient. In this case, anarea may be created between the first, second lead frame and the housing110. Accordingly, the first, second lead frame exposed in the area 200is oxidized by moisture included in air. As time passes, thisoxidization of the first, second lead frame progresses to an areaadjacent to the light emitting device and an air gap (not shown) iscreated between the light emitting device 120 and the first, second leadframe. When the light emitting device 120 is operating, it generatesheat back toward the light emitting device 120 and the air gap (notshown) blocks a passage for emitting heat through the first, second leadframe.

In the first embodiment, a metal layer 145 is positioned in an area 200defined by a distance between the housing 110 and the respective first,second lead frame 131, 132. The metal layer 145 is filled in the area200 to prevent air, moisture or foreign substances from entering thearea 200. Accordingly, the metal layer 145 can prevent the first, secondlead frame 131,132 exposed in the area 200 from being oxidized bymoisture. In addition, the metal layer 145 prevents oxidization of thefirst and second lead frame 131,132, thereby obtaining unique electriccharacteristics of the first and second lead frame. The metal layer 145is extended from the second section of the first and the second leadframe 131,132 to the third section of the first and the second leadframe exposed at an outside of the housing. The metal layer 145 preventsoxidization, which is caused by exposure to outside air, of the thirdsection of the first and second lead frame 131,132. In addition,deterioration of the electric characteristics due to the oxidization canbe prevented. The metal layer 145, which is extended from the area 200onto the third section of the first, second lead frame, may be formedthrough a plating process. However, a method of forming the metal layeris not limited to the plating process. Any process is possible as longas it is capable of forming the metal layer in the area 200 and on thelead frame 131, 132. A material of the metal layer 145 may include Tin.Tin is excellent and more economic compared with other metals excludinggold, in terms of heat transfer characteristics. In addition, wheninstalling the light emitting device package 100 on a substrate withlead by the surface mount technology; tin has an excellent electricbonding capacity and conductance with the lead. Accordingly, the metallayer improves radiation heat characteristics when heat in operation ofthe light emitting device is radiated to the substrate along the firstor second lead frame 131,132.

FIG. 3 is a cross sectional view of showing the light emitting devicepackage according to the second embodiment.

The description repeated in the first embodiment will be omitted in thedescription of the second embodiment.

In FIG. 3, a sealant 146 of the second embodiment seals the area 200between the housing 100 and the respective first and second lead frame131,132. The sealant 146 seals the area to prevent air, moisture,foreign substances from entering. Accordingly, it prevents the first andsecond lead frame 131,132 exposed to the area 200 from being oxidized bymoisture.

For the sealant 146, it is preferred to use a material which can adherewell to the housing and the first and second lead frame 131,132. Forexample, it is preferred to use a material having the same or similarheat expansion coefficient as/to that of the housing or the first andsecond lead frame 131,132. In other words, it is preferred to use sameresin as the housing 110 or same metal as the first and second leadframe 131, 132.

In case the sealant 146 is metal, it prevents deterioration of uniqueelectric characteristic of the first and second lead frame 131,132caused as time passes.

A sealing method may be spray painting process, injection moldingprocess and so on. It is not limited to the process like this.

A metal film 147 may be formed on a surface of the third section of thefirst and the second lead frame exposed to an outside of the housing.The metal film 147, which is formed on the third section of the firstand second lead frame, may be made by a plating process. The metal film147 includes Tin.

FIGS. 4-7 are views of showing a manufacture process of the lightemitting device package according to the first embodiment.

As shown in FIG. 4, the first lead frame 131 and the second lead frame132 are positioned in an injection apparatus, and the first lead frame131 and the second lead frame 132 and the housing are made integrally byinjecting resin to the apparatus. The first lead frame 131 and thesecond lead frame 132 are made of metal or alloy having copper as a maincomponent, and surfaces of which may have more than one plating layersuch as a nickel plating layer, a gold plating layer or silver platinglayer. In this embodiment, the surfaces of the first lead frame 131 andthe second lead frame 132 have a silver plating layer (not shown).

In FIG. 5, the light emitting device 120 is installed on the second leadframe 132, and the light emitting device 120 is electrically connectedto the first lead frame 131 and the second lead frame 132 through a wire122.

In FIG. 6, an encapsulant 130 is injected to the cavity 114 of thehousing 110. The encapsulant 130 may include fluorescent material. Bytrimming and forming the first lead frame 131 and the second lead frame132, the lead frames are made to contact sides and bottom surfaces ofthe housing 110. During the trimming and forming process for the leadframes, an area 200 may be created between the lead frame 131, 132 andthe housing 110.

As shown in FIG. 7, a metal layer 145 is filled in the area 200, and themetal layer is formed on the first lead frame 131 and the second leadframe 132 which are exposed at the outside of the housing. The metallayer 145 may be formed through a plating process, and for example Tinmay be used for the metal layer.

FIG. 8 is a view of showing a light emitting device package according toa third embodiment. The description repeated in the first embodiment isomitted in a description of the third embodiment.

As shown in FIG. 8, the light emitting device package according to athird embodiment comprises a housing 110 having a cavity 114, a first,second lead frame 131,132, a light emitting device 120 and anencapsulant 130.

A part of the first, second lead frame 131,132 are projected toward anoutside of the housing 110, and unlike the first embodiment the leadframes are not contacted with the sides and the bottom of the housing110. However, during a trimming process for the first, second lead frame131,132, an area 200 may be created between the lead frames 131, 132 andthe housing 110, and a metal layer 145 is formed to fill the area 200.

FIGS. 9-12 are views of showing a manufacture process of the lightemitting device package according to the second embodiment.

As shown in FIG. 9, the first lead frame 131 and the second lead frame132 are positioned in an injection apparatus, and the first lead frame131 and the second lead frame 132 and the housing are made integrally byinjecting resin to the apparatus. The first lead frame 131 and thesecond lead frame 132 are made of metal or alloy having copper as a maincomponent, and surfaces of which may have more than one plating layersuch as a nickel plating layer, a gold plating layer or silver platinglayer. In this embodiment, the surfaces of the first lead frame 131 andthe second lead frame 132 have a silver plating layer (not shown).

In FIG. 10, the light emitting device 120 is installed on the secondlead frame 132, and the light emitting device 120 is electricallyconnected to the first lead frame 131 and the second lead frame 132through a wire 122.

As shown in FIG. 11, an encapsulant 130 is injected to the cavity 114 ofthe package body 110. By trimming and forming the first lead frame 131and the second lead frame 132, the lead frames are made to contact sidesand bottom surfaces of the housing 110. During the trimming and formingprocess for the lead frames, an area 200 may be created between the leadframe 131, 132 and the housing 110.

As shown in FIG. 12, the area 200 is sealed by a sealant 146 and amaterial of the sealant may be a metal or resin. A metal layer 147 isformed on the first lead frame 131 and the second lead frame 132 whichare exposed at the outside of the housing. The metal layer 147 may beformed through a plating process, and for example Tin may be used forthe metal layer.

FIG. 13 is a view of showing a light emitting device package accordingto a fourth embodiment. The description repeated in the secondembodiment is omitted in a description of the fourth embodiment.

As shown in FIG. 13, the light emitting device package according to afourth embodiment comprises a housing 110 having a cavity 114, a first,second lead frame 131,132, a light emitting device 120 and anencapsulant 130.

A part of the first, second lead frame 131, 132 is projected toward anoutside of the housing 110, and unlike the first embodiment the leadframes are not contacted with the sides and the bottom of the housing110. However, during a trimming process for the first, second lead frame131,132, an area 200 may be created between the lead frames 131, 132 andthe housing 110, and the area 200 is sealed by the sealant 146.

Although in the above embodiments the plural lead frames are made by atrimming and forming process, a shape of one of the lead frames may be abar for penetrating the package body in the up and down direction, andthe other lead frame may be formed by the trimming and forming process.In addition, the lead frames may have a metal film thereon.

What is claimed is:
 1. A light emitting device package comprising: ahousing including a cavity and an upper section over a lower section; alight emitting device positioned in the cavity; a lead frame including afirst section which is electrically connected to the light emittingdevice and overlaps the cavity, a second section which is extended fromthe first section and disposed between the upper section and the lowersection, and a third section which is extended from the second sectionand at least partially overlaps an external surface of the lowersection; and a gap disposed between the second section of the lead frameand at least one of the upper section and the lower section of thehousing; wherein the gap is extended in a direction toward the cavityfrom an outer edge region between the upper section and the lowersection of the housing, wherein the gap has a length shorter than thatof the second section of the lead frame, wherein the second section ofthe lead frame includes a first region directly contacted with thehousing and a second region corresponding to the gap, wherein the gaphas a smaller height than a thickness of the light emitting device. 2.The light emitting device package as set forth in claim 1, wherein thegap includes a first gap between the second section of the lead frameand the upper section of the housing and a second gap between the secondsection of the lead frame and the lower section of the housing.
 3. Thelight emitting device package as set forth in claim 1, wherein the firstgap is vertically overlapped with the second gap in the housing.
 4. Thelight emitting device package as set forth in claim 1, furthercomprising a metal layer disposed in the gap.
 5. The light emittingdevice package as set forth in claim 4, wherein the metal layer isdirectly contacted with a portion of the second section of the leadframe.
 6. The light emitting device package as set forth in claim 5,wherein the metal layer includes a first metal layer disposed betweenthe second section of the lead frame and the upper section of thehousing.
 7. The light emitting device package as set forth in claim 6,wherein the metal layer includes a second metal layer disposed betweenthe second section of the lead frame and the lower section of thehousing.
 8. The light emitting device package as set forth in claim 5,wherein the metal layer is extended to a surface of the third section ofthe lead frame.
 9. The light emitting device package as set forth inclaim 4, wherein a material of the metal layer includes Tin.
 10. Thelight emitting device package as set forth in claim 1, furthercomprising a sealant member disposed in the gap.
 11. The light emittingdevice package as set forth in claim 10, wherein the sealant member isformed of a resin material.
 12. The light emitting device package as setforth in claim 10, wherein the sealant member is formed of a metalmaterial.
 13. A light emitting device package comprising: a housingincluding a cavity and an upper section over a lower section; a lightemitting device positioned in the cavity; a first lead frame disposed ona bottom surface of the cavity; a second lead frame disposed on thebottom surface of the cavity and spaced apart from the first lead frame;a gap disposed between at least one of the first and second lead framesand the upper section of the housing, wherein each of the first andsecond lead frames includes a first section which is electricallyconnected to the light emitting device and overlaps the cavity, a secondsection which is extended from the first section and disposed betweenthe upper section and the lower section, and a third section which isextended from the second section and at least partially overlaps anexternal surface of the lower section, wherein the gap is disposedbetween the second section and the upper section and the lower sectionof the housing, wherein the gap is extended in a direction toward thecavity from an outer edge region between the upper section and the lowersection of the housing, wherein the gap has a length shorter than thatof the second section, wherein the second section includes a firstregion directly contacted with the housing and a second regioncorresponding to the gap, wherein the first region has a differentthickness from the second region in the second section.
 14. The lightemitting device package as set forth in claim 13, further comprising asealant member between the housing and the second section of the leadframe.
 15. The light emitting device package as set forth in claim 13,wherein the gap includes a first gap between the first lead frame andthe upper section of the housing and a second gap between the secondlead frame and the upper section of the housing.
 16. The light emittingdevice package as set forth in claim 15, further comprising a firstsealant member disposed in the first gap and the second sealant memberdisposed in the second gap.
 17. The light emitting device package as setforth in claim 16, wherein the first sealant member is formed of thesame material as the second sealant member.
 18. The light emittingdevice package as set forth in claim 17, wherein the first and secondsealant members are formed of a resin material or a metal material. 19.The light emitting device package as set forth in claim 13, wherein asurface of the third section of each of the first and second lead framesincludes a metal protection layer including at least one of nickel,gold, or silver, wherein the metal protection layer is not contactedwith a surface of the first section of each of the first and second leadframes.
 20. The light emitting device package as set forth in claim 13,wherein a lower surfaces of the first and second sections of each of thefirst and lead frames form a substantially planar surface.